The program to control the entry of illegal drugs into the country was a failure in 1987. If the program had been successful, the wholesale price of most illegal drugs would not have dropped substantially in 1987.

13.   The argument in the passage depends on which of the following assumptions? E

(A) The supply of illegal drugs dropped substantially in 1987.

(B) The price paid for most illegal drugs by the average consumer did not drop substantially in 1987.

(C) Domestic production of illegal drugs increased at a higher rate than did the entry of such drugs into the country.

(D) The wholesale price of a few illegal drugs increased substantially in 1987.（E）

(E) A drop in demand for most illegal drugs in 1987 was not the sole cause of the drop in their wholesale price.

实在搞不懂怎么选E的

控制非法药物的program失败了，非法药物的价格下降的很厉害。但是如果成功的话，

就不会下降的很厉害。

E：取非。如果是需求下降影响了价格下降，则说明非法药物价格下降，就不是program

的问题了。从而weaken结论。